1. The development of a (mode-locked) picosecond flash photolysis instrument has been completed and tested. The spectrometer has a sensitiviey of plus or minus 0.01 optical density units and operates at four wavelengths 1064, 532, 355, and 266 nanometers with energies of 60, 10, 1, and 2 millijoules respectively. A dye laser attachment has been constructed so as to improve the tunable excitation range. 2. Design and construction of a nitrogen-laser photolysis apparatus in the subnanosecond range has been started. This instrument overcomes many of the problems normally encountered in conventional photolysis instrumentation and provides the biochemist with a versatile flash photolysis instrument. 3. A fluoresence lifetime spectrometer employing a pulsed tunable UV laser has been designed and partially constructed. Intrinsic fluorescence lifetime and energy transfer measurements on proteins are plagued by the necessity of deconvoluting the instrumental response from the decay curves. This new instrument has a response time of less than 200 picoseconds and will permit a direct measurement of intrinsic fluorescence in proteins.